Layering of Air Gaps To Improve Armor Protection

ABSTRACT

According to one embodiment, an armor system comprises a plurality of layers of armor and a plurality of air gap layers. The plurality of air gap layers are located in between two or more layers of the plurality of layers of armor. Each air gap layer is located at a respective depth in the plurality of layers of armor. At least a first air gap layer of the plurality of air gap layers is located at a first depth from an outer side of the armor system. The outer side is located toward a projectile impact site. At least a second air gap layer of the plurality of air gap layers is located at a second depth from the outer side. The first air gap layer has a thickness greater than the second air gap layer.

TECHNICAL FIELD

This invention relates generally to the field of armor systems and more specifically to light weight armor systems comprising air gap layers of varying thicknesses that are operable to protect against shape charges (e.g., an explosively formed penetrator (EFP)), other explosive devices, hypervelocity impacts and/or ballistic devices.

BACKGROUND

Improvised Explosive Devices (IEDs) and shape charges such as Explosively Formed Penetrators (EFPs) have accounted for a large number of combat casualties. Lethality of EFPs comes in part from the shape and arrangement of a concave copper cone, called the liner, which transforms into a forceful jet of fluidic metal which easily perforates steel armor. Despite focused efforts on armor development, Mine Resistant Ambush Protected (MRAP) vehicles and other armored vehicles still cannot defend against these threats. More recently, armor solutions such as the FRAG Kit 5 have been used to protect military vehicles such as Humvees. However, these armor solutions typically weigh around 200 lb/f t². Since nearly all army vehicles are thousands of pounds overweight, even without any additional armor protection solution, most of these approaches have proved impractical.

SUMMARY OF THE DISCLOSURE

According to one embodiment, an armor system comprises a plurality of layers of armor and a plurality of air gap layers. The plurality of air gap layers are located in between two or more layers of the plurality of layers of armor. Each air gap layer is located at a respective depth in the plurality of layers of armor. At least a first air gap layer of the plurality of air gap layers is located at a first depth from an outer side of the armor system. The outer side is located toward a projectile impact site. At least a second air gap layer of the plurality of air gap layers is located at a second depth from the outer side. The first air gap layer has a thickness greater than the second air gap layer.

An air gap may provide a distance in which an armor layer located in front of the air gap that is impacted by a projectile may flex into. Impact with a projectile device may cause flexing of an impacted outer armor layer into an air gap layer which may advantageously change the trajectory of the projectile device. For example, in some embodiments, an air gap may cause a projectile to gain a tumble.

In some embodiments, having an air gap with a greater thickness located closer to an impact site may cause a greater initial change in deflecting the trajectory of an incoming projectile. For example, an air gap with a greater thickness located closer to an impact site in the armor system may substantially lower the impact force exerted on the next layer of armor and may thereby slow the projectile and/or reduce damage by the projectile to the next layer of armor.

Air gap layers may comprise air, a gas and/or materials with easily yielding properties. Air gaps are described in detail later in the specification.

Certain embodiments of the invention may provide one or more technical advantages. A technical advantage of one embodiment may include the capability to add a tumble to the path of a projectile device. A technical advantage of one embodiment may include the capability to change the trajectory of a projectile device. A technical advantage of one embodiment may include the capability to slow down particles of a projectile. A technical advantage of one embodiment may include the capability to withstand and resist multiple impacts from particles of a projectile device. A technical advantage of one embodiment may also include the capability to increase impact time. A technical advantage of one embodiment may also include the capability to lower the force exerted on one or more armor layers of an armor system. A technical advantage of one embodiment may also include the capability to decrease the overall impact of a projectile. A technical advantage of one embodiment may also include the capability to decrease the shape change ability of a projectile.

Further technical advantages of particular embodiments of the present disclosure may include an armor system that is lighter weight than conventional armor. A lightweight armor system of the present disclosure may be capable of protecting against a similar threat as a heavier conventional armor system. Yet another technical advantage of one embodiment may be a relatively low cost solution to provide protection against a variety of projectiles and high velocity impacts. In particular, armor systems comprising one or more air gap layers in accordance with the present disclosure may protect against an shape charge such as an EFP, other explosive devices such as IED's, other projectile threats, bullets, ballistic threats and/or forms of hypervelocity impact.

Various embodiments of the invention may include none, some, or all of the above technical advantages. One or more other technical advantages may be readily apparent to one skilled in the art from the figures, descriptions, and claims included herein.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and its features and advantages, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which:

FIG. 1 shows an armor system having layered air gaps of varying thickness, according to one example embodiment;

FIG. 2 shows another armor system having layered air gaps of varying thickness, according to one example embodiment;

FIG. 3 shows a vehicle comprising an armor system of the disclosure, in accordance with one example embodiment;

FIGS. 4A and 4B shows an exemplary path of an explosively formed penetrator (EFP) through a prior art armor system not having air gap layers, wherein, FIG. 4A depicts an example shallow-disk shaped EFP making contact with a first layer of armor located on an outer side of the armor system and FIG. 4B depicts the EFP now formed into a missile shaped structure as it penetrates through layers of prior art armor; and

FIGS. 5A, 5B and 5C illustrate an exemplary path of an explosively formed penetrator (EFP) through one embodiment of an armor system of the disclosure as shown in FIG. 1 having air gaps layers wherein FIG. 5A depicts an example shallow-disk shaped EFP contacting an outer side of the armor system; FIG. 5B depicts the EFP as it penetrates through a first layer of armor which flexes into a first air gap; and FIG. 5C illustrates the EFP as it penetrates through a second layer of armor which flexes into a second air gap considerably slowing the impact and shape change ability of the EFP, according to one example embodiment.

DETAILED DESCRIPTION OF THE DISCLOSURE

It should be understood at the outset that, although example implementations of embodiments of the invention are illustrated below, the present invention may be implemented using any number of techniques, whether currently known or not. The present invention should in no way be limited to the example implementations, drawings, and techniques illustrated below. Additionally, the drawings are not necessarily drawn to scale.

Teachings of certain embodiments recognize that armor systems may be used to provide protection against and/or reduce impact of various projectiles such as but not limited to shaped charges, EFP's, IEDs, ballistic devices, other explosives and hypervelocity impacts. Armor systems of the disclosure may be used in conjunction with any vehicle, such as but not limited to, military vehicles, convoy vehicles and/or personnel carriers and may be useful to protect personnel and equipment in war zones.

On the battlefield, shape charges such as explosively formed penetrators (EFPs), also known as explosively formed projectiles, pose serious threat to equipment and personnel. EFPs and other shape charges may have the ability to pierce through the armor of a vehicle and injure or kill the occupants inside.

Various configurations of shape charges and EFPs have been developed and several are capable of penetrating extremely thick and heavy armor. Therefore, merely adding more armor layers to protect against a shape charge may result in a vehicle that is overweight and less effective on the battlefield. In accordance with a particular embodiment of the present disclosure, a lightweight armor system may be capable of stopping a projectile or significantly reducing its destructive capability.

While not wishing to be bound to any particular theory, the present section provides a brief description of how high energy explosives and shape charges may achieve their lethality. High explosives may be extremely powerful because of their ability to rapidly release energy in the form of heat and pressurized gas. The extremely fast rate at which this energy may be discharged gives a high explosive its strength. Rapid discharge of a large amount of energy into a small space may generate shock waves. For example, rapidly released energy may compress neighboring air or surrounding material that further increase its velocity. The compressed air may then rapidly propagate outward and create a shock wave.

When a high explosive is detonated, an explosion may begin at a small portion at the edge of the explosive. This explosion may create a shock wave that may propagate through the rest of the explosive. When this shock wave comes in contact with a portion of the high explosive that has not yet exploded the shock wave detonates the unexploded explosive. Thus, the additional explosion causes the shock wave to increase in velocity.

By exploiting the properties of a high explosive, in conjunction with certain geometric configurations, a more powerful and more focused blast may be accomplished. Shape charges utilize properties of high explosives and a conical geometric shape, lined with a metal liner, to achieve an explosion that can reshape material from the metal liner into a penetrating configuration at the same time accelerating it by a high energy explosion.

Inertial forces of a material (e.g., metal from a metal liner) that are being propelled by an explosion from rest to a hypervelocity may affect the molecular structure of the material. A hypervelocity may be a velocity of over 6,700 miles per hour. Acceleration from rest to a hypervelocity generates extremely high inertial forces. These inertial forces may be significantly greater than the molecular forces holding the particular material together. As a result, the material may change its form and may convert from a solid to a liquid with the dominating inertial forces guiding the flow of the material.

EFPs and other shape charges use these principles while unleashing their explosive power. A shaped charge may be able to pierce a thickness of steel armor equal to six-times its diameter.

When a shape charge is detonated a shock wave that detonates the charge reaches the tip of its metal liner. The liner tip may accelerate forward due to inertial forces and reach a hypervelocity changing the solid metal into a fluid. As the shock wave pushes the liner metal fluid towards center and since there is already metal occupying the center, the metal gets pushed out in two directions, some of the metal gets thrust in the direction of motion and becomes part of the jet or the penetrating portion of the shaped charge, while the rest of the metal gets pushed back towards the explosive and becomes part of the slug, the slow bulky portion of the shaped charge.

The remaining part of the conical liner may take the shape of a flat sheet and the shock wave may then impart additional momentum to the flat sheet giving it a final solid push. The shaped charge finally detaches from its casing.

The fluid metal has a varying velocity with length velocity decreasing farther down. For example, a jet tip of the fluid metal may be traveling much faster than a slug. The result may be an ultra-fine long penetrator traveling at an extremely high speed which may go through armor with a thickness of about six times the diameter of the charge. In accordance with one embodiment of the present disclosure, the speed of the tip of a shape charge may be substantially decreased by an air gap embedded within an armor system of the disclosure.

However, shaped charges are not as effective and efficient to pierce armor from a distance, since a jet of fluid material can continue to stretch and will eventually break apart before it contacts a distant target.

An EFP is a specific type of shaped charge designed to pierce armor from a distance. A wide range of EFPs have been designed depending on the desired effect. An EFP structure may provide a distinct aerodynamic advantage over shaped charges. EFPs are typically shaped as semi-spherical dishes (rather than conical shapes as described above) that may be covered by a metal liner. The metal liner may be copper, or any other suitable metal that behaves similar to a fluid when subjected to extremely high inertial forces.

By having a more shallow dish shape an EFP jet does not become quite as concentrated as a shape charge jet described in sections above. Often an EFP metal becomes a single slug rather than a separate slug and jet. A minor jet may be present near the tip, but for the most part, the slug does not have a defined shape. EFPs typically have a larger slug that stays together better, but may have lower penetration attributes. For example, an EFP may be able to pierce a thickness of steel armor equal to the charge diameter. However, an EFP liner may be concentrated together such that the metal does not break apart before it reaches its target, making it efficient to strike distant targets.

As set forth earlier, geometry of the curvature of the liner before detonation may control the shape an EFP changes into after detonation. Particular shapes may be found to provide optimum aerodynamic and penetration attributes. The shape of an EFP may be important to its ability to penetrate. An EFP with a smaller surface area may penetrate easier. This may be the result of the higher stress that the EFP imparts over a smaller surface area of the armor it is penetrating. This may result in greater penetration. In accordance with one embodiment of the present disclosure, surface area of the tip of an EFP may be increased by an air gap embedded within an armor system. In some embodiments, increasing the surface area of the tip of an EFP may provide a technical advantage by making it easier to decrease and/or stop penetration by an EFP using a lightweight armor system.

An EFP may travel at hypervelocity regimes over 6700 miles per hour. A shock wave that accelerates the metal liner to these types of velocities may cause the metal liner of an EFP to behave as if it were a fluid. Fluid effects caused by the inertial forces generated by the explosion may in part contribute to the EFPs ability to penetrate.

As the fluid from an EFP tip penetrates armor, the armor may exert a drag force upon the tip of the EFP. However, instead of transmitting this force throughout the entire EFP, as would occur if the EFP were a solid, the tip portion of the EFP that is subjected to the drag force, may fall away from the sides of a hole being created in the armor. Thus, instead of slowing down the entire EFP, only a small portion of the EFP may experience drag from the armor while the rest of the EFP maintains its velocity as it travels through the hole in the armor.

Additionally, as the portion of the metal tip gets dragged backwards by the armor, the EFP may reshape itself into a better penetrator. This may result when the edges of the EFP may be somewhat consumed as they are pushed to the rear of the EFP reshaping the EFP to become a thinner and more effective penetrator. For example, material from EFPs may be reshaped into a missile shape. The EFP, due to this reshaped form, effectively slides through the hole formed in the armor, as opposed to having large friction forces from the armor slow the entire EFP. Accordingly, an EFP effectively lubricates the armor walls through which it is penetrating and despite its poor initial shape, is effectively able to reshape and bore through thick armor. In some embodiments, an armor system having air gaps according to some embodiments of the disclosure, may be able to reduce the reshaping ability of an EFP.

In addition, an EFP during its hypervelocity flight may split into a series of metal blobs or metal particles comprising leaders that are smaller, but travel faster and slugs which may be slower and bulkier. Several leader particles such as a primary leader and a secondary leader and several slugs such as a primary slug and a secondary slug may be present. A good EFP normally has all these metal particles well aligned with out a large pitch or yaw. Accordingly, an armor to protect form such an attack must be capable of withstanding multiple impacts.

Much of the lethal damage from an EFP is due to the behind armor effects (BAE). When an EFP penetrates armor, it may launch spall into the vehicle. Spall refers to the fragments of armor that the EFP may cause to break off and accelerate into the interior of the vehicle. This material may be extremely hot and may be moving at an extremely high velocity. As a result, these armor fragments may hit nearly everything within the personnel compartment of the vehicle and may cause extreme damage to the vehicle and equipment inside and injury or death to any occupants.

Damage from EFPs may also result from the overpressure blast that may send highly compressed air outwards at an extremely high velocity. The overpressure alone may cause blindness, deafness, and death. The overall effect of an EFP penetrating a vehicle may be similar to a fragmentation grenade being detonated within the vehicle.

In accordance with one embodiment of the present disclosure, an armor system having air gap layers may be capable of significantly reducing destructive capability of a shape charge, an EFP, a high explosive, as well as any high velocity impact by slowing the speed of the respective projectile device.

FIGS. 1 and 2 show example embodiments of armor systems according to some embodiments of the disclosure. However, teachings recognize that other armor systems as described in the present specification may be made and/or modified and used.

FIG. 1 shows exemplary armor system 150 comprising three layers of armor 155 a, 155 b and 155 c, according to one example embodiment. However, teachings recognize use of additional number of armor layers (or armor panels) 155 in armor system 150. In non-limiting examples, an armor system 150 of the present disclosure may comprise three or more layers of armor 155.

In some embodiments, armor system 150 may comprise two air gap layers 140 a and 140 b as depicted in FIG. 1. However, teachings recognize use of additional number of air gap layers 140 in armor system 150 a. As depicted in FIG. 1, air gap layer 140 a has a thickness d₁ and air gap layer 140 b has a thickness d₂, wherein d₁>d₂.

In one embodiment, armor system 150 may comprise additional air gap layers 140 (not expressly depicted) where the thickness d₁ of air gap layer 140 a is greater than the thickness d_(x) (wherein x represents the number of the air gap layer, for example, x=1 for 140 a, x=2 for 140 b, x=3 for 140 c, x=4 for 140 d, . . . ) of all the additional air gap layers 140.

In one embodiment, armor system 150 may comprise additional air gap layers 140 (not expressly depicted) where the thickness of each subsequent air gap layer may be lesser than the thickness of an air gap layer preceding it.

In some embodiments, armor layers 155 may be comprised of fiber made materials. Non limiting examples of fiber made materials include e-glass, s-glass, an aramid fiber (such as Kevlar), carbon nanotubes, carbon fibers, aluminum fibers and combinations thereof.

As set forth earlier air gap layers 140 may be comprised of air, of a gas, or of an easily yielding material. Exemplary gases that may be used may include any inert gas, argon, oxygen. An easily yielding material may be a soft material such as a plastic. An easily yielding material may be a material that may have very little structural support, such as but not limited to, Styrofoam and/or aerogels. An easily yielding material may be a material having strong structural support such as but not limited to carbonized hard steel. An easily yielding material in some embodiments may also include a naturally strong structural material for example a material comprising different shapes such as but not limited to, honeycombs, cylinders or pyramids. Use of several other easily yielding materials not expressly described herein are also contemplated and the present disclosure is not limited in any way to the examples listed.

In some embodiments, an air gap 140 may provide a distance into which a preceding armor panel may flex. Due to the presence of an air gap layer (e.g. 140 a), a preceding armor panel (e.g., 155 a) may not have a solid backing and hence, the entire armor panel may bend back (flex) towards the air gap following impact of a projectile (see also FIGS. 5B and 5C). For example, in one example embodiment, a 12″×12″×¾″ armor panel flexed back approximately 3 to 4 inches into an air gap behind it. In some embodiments, flexing of an armor panel 155 into an air gap 140 that has a respective thickness d, may increase projectile impact time and/or may lower force exerted by a projectile the next armor panel, and/or may increase overall energy absorption from the incoming device. High speed video experimental testing have shown one or more of the above listed advantages.

In some embodiments, an air gap 140 according to the present disclosure may throw off the trajectory of an incoming projectile 100. For example, projectiles 100, which may often be missile shaped, although not necessarily limited to missile shaped objects, while penetrating through conventional armor systems, may be subjected to forces that may cause them to spin out of axis. However, since projectiles 100 may typically be fully constrained within the material of conventional armor systems, the projectile 100 may continue to stay aligned in its trajectory. However, when a projectile 100 is suddenly subjected to an air gap 140 in an armor system 150 in accordance with embodiments of present disclosure the, the projectile 100 may gain a tumble. The present inventors have verified such a tumble gain in experiments.

Projectile 100 may be any high explosive device, such as but not limited to a shape charge, an EFP, an IED, a landmine, a high energy explosive, a ballistic device and/or any hypervelocity impact. However, teachings of certain embodiments recognize that present armor systems 150 may provide protection or mitigate the effects of any other projectile type that may be operable to penetrate armor.

As further depicted in FIG. 1, an outer side 151 of an armor system 150 of the disclosure may refer to a side of armor system 150 that receives initial impact of a projectile 100. Accordingly, in the example embodiment depicted in FIG. 1, armor layer 155 a may correspond to an armor layer located at a shallowest depth in armor system 150 and air gap 140 a may refer to a first air gap located adjacent or toward an outer side 151 (or toward a shallowest depth) of armor system 150. An inner side 152 of an armor system 150 of the disclosure may refer to a side of armor system 150 that is located away from the initial impact of a projectile 100. Accordingly, in the example embodiment depicted in FIG. 1, armor layer 155 c may correspond to a deepest depth in armor system 150 and air gap layer 140 b may refer to a second air gap layer located adjacent or toward inner side 152 (or toward a deepest depth) of armor system 150.

FIG. 2 shows another exemplary armor system 150 a comprising four layers of armor 155 a, 155 b, 155 c and 155 d, according to one example embodiment. In some embodiments, armor system 150 a may comprise three air gap layers 140 a, 140 b and 140 c as depicted in FIG. 2. In some embodiments, armor system 150 a may comprise two air gap layers 140 a and 140 b or 140 a and 140 c (not expressly depicted in these combinations). Additionally, teachings recognize use of additional number of armor plates 155 and/or air gap layers 140 in armor system 150 a.

As depicted in FIG. 2, air gap layer 140 a has a thickness d₁, air gap layer 140 b has a thickness d₂ and air gap layer 140 c has a thickness d₃ wherein d₁ >d₂>d₃. In one embodiment, air gap layers 140 a, 140 b and 140 c may have thicknesses such that d₁>d₂ and d₁>d₃ in armor system 150 a (not expressly depicted). In one embodiment, in one example armor system 150 a, the thicknesses of subsequent air gaps may be equal to each other, for example d₂=d₃ and d₁>d₂ and d₃, (not expressly depicted).

FIG. 3 depicts a vehicle 20, such as but not limited to a military vehicle, that may be equipped with an armor system 150 having a plurality of armor panels 155 and two or more air gaps 140 of varying thicknesses d in accordance with the present disclosure. Armor system 150 may be comprised on exterior of vehicle 20. Occupants and equipment of vehicle 20 may be protected by armor system 150 from the penetrating effects of a projectile (not expressly depicted) which may target vehicle 20. Vehicle 20 may be maneuverable and effective on a battlefield while it is equipped with an armor system 150 in accordance with embodiments of the present disclosure.

According to some embodiments, present armor systems such as 150 and/or 150 a may comprise armor and air gaps and may be from about 1 mm to several inches in thickness.

Other armor systems that do not employ air gap layers as taught herein may be considerably heavier and thicker. For example, conventional armor systems, without air gap layers as taught in the present application, may be several inches thick. In another example, mere addition of two panels of armor to an existing conventional armor system may add an additional weight of about 20 lb/ft² or more depending on the type of armor material used.

If vehicle 20 were equipped with any existing armor system or armor system solution, its maneuverability and effectiveness in protecting against projectiles 100 as described here may be diminished.

FIG. 4A depicts an example shallow-disk shaped EFP 100 making contact with a first armor layer 155 a of a prior art armor system 150 b where first armor layer 155 a is located on an outer side 151 of the armor system 150 b. FIG. 4B shows an exemplary path of EFP 100 through a prior art armor system 150 that does not have air gap layers. FIG. 4B depicts penetration through layers 155 a, 155 b and 155 c by EFP 100. As depicted, EFP 100 is now reshaped into a missile shaped structure and slides through armor as it penetrates through layers of the prior art armor system 150 b. Since EFP 100 may be fully constrained within armor material of armor system 150 b the EFP stays aligned on its trajectory through all the layers of the prior art armor system 150 b.

FIGS. 5A, 5B and 5C illustrate an exemplary path of an EFP 100 through an armor system 150 having two air gaps layers 140 a and 140 b according to one example embodiment of the disclosure. FIG. 5A shows shallow-disk shaped EFP 100 making initial contact with an outer side 151 of armor system 150. Armor system 150 is configured similar to exemplary armor system 150 shown in FIG. 1. In some embodiments, armor system 150 as shown in FIGS. 5A-5C may be comprised on the exterior of a vehicle 20.

FIG. 5B depicts penetration by EFP 100 into a first armor layer 155 a and shows flexing of the entire armor layer 155 a into a first air gap 140 a having a thickness d₁ in response to impact by EFP 100. As set forth earlier, in some embodiments, flexing of armor layer 155 a may cause a tumble in the path of EFP 100 and/or throw EFP 100 off its trajectory and/or lower the force exerted on a following panel of armor 155 b, and/or may increase the overall energy absorbed by the armor system 150 and/or may significantly slow EFP 100 and/or may slow reshaping ability of EFP 100. EFP 100, with the gained tumble, may re-collide with the next layer of armor 155 b with a reduced penetration ability.

FIG. 5C illustrates EFP 100 penetrating through a second armor layer 155 b and shows flexing of armor panel 155 b into a second air gap 140 b having a thickness d₂ (which may be thinner than d₁). In some embodiments, passing through second air gap 140 b may further add tumble and/or reduce speed and/or impact and/or shape change ability and/or destructive ability of EFP 100. In some embodiments, subsequent encounters with two or more air-gaps may render EFP 100 unable or ineffective to penetrate armor layer 155 c leaving the occupants and equipment behind protective armor layer 155 c protected. In some embodiments, one or more air gaps may increase the overall energy absorption capacity of armor system 150.

Various embodiments of armor systems 150 of the disclosure having two or more air gaps 140 have been simulated and tested within several EFP and hypervelocity solutions and air gaps 140 have been shown to confer one or more of the various advantages outlined above to armor systems 150.

For example, the present inventors conducted Aberdeen tests using armor panels 155 backed by air-gaps 140 and found that an armor panel 155 flexed a respective distance that was related to how much energy was remaining in the EFP. In a specific example embodiment that was tested, an armor panel 155 located near the front or near the outer side 151 of an armor system 150 having dimensions of 0.75″×24″×24″ flexed backwards about 3″, while an armor panel having the same dimensions located near the back or near the outer side 152 of armor system 150 flexed only about 0.5″ to 1″. These observations were verified by high speed video as well as by examination of whether or not delaminated fibers were being crushed.

In another example, the present inventors performed Aberdeen tests with armor systems 150 having air gaps and showed significantly better protection as compared to equivalent armor systems 150 b lacking air gaps.

Teachings of certain embodiments recognize that flexing of armor panels following impact with an EFP may cause an armor panel to bend a distance three times or more of its original thickness.

Teachings of certain embodiments recognize that in cases of ballistic impact from bullets flexing of panels may be relatively minimal.

Teachings of certain embodiments recognize that in an armor system desiring EFP (or hypervelocity) protection, if an air gap layer has a respective smaller thickness, the EFP may cause a front armor panel to flex completely into the air space behind it and contact a next armor panel. Accordingly, teachings of certain embodiments recognize that if an armor panel flexes to completely use up an air gap the air gap may be no longer effective.

On the contrary, if an air gap has a respective thickness d that may be too large, an anti-EFP armor system may be highly successful in stopping destruction from an EFP. However, very thick air gaps also increase the overall thickness of an armor start which make it impractical for use. Accordingly, teachings of certain embodiments recognize that providing air gap layers having finely tuned thicknesses may mitigate effects of different types of projectiles.

Accordingly, in some embodiments, the present disclosure describes armor systems having a plurality of air gap layers with each air gap layer having a thicknesses d that barely get compressed based on the nature and force of an incoming projectile. In some embodiments, an air gap layer thickness d may vary with respect to location of the air gap with respect to depth in the armor system. Accordingly, in some embodiments, air gap layers located in the armor system closer to projectile impact may have a larger thickness as compared to air gap layers located in deeper layers of the armor system and away from the force of the initial impact. Teachings of certain embodiments recognize that, designing an armor system in accordance with some embodiments of this disclosure may provide an efficient design that may be capable of reducing and/or eliminating destruction by an incoming projectile in addition to being of a manageable weight and/or size for maneuverablity and handling.

Teachings of certain embodiments recognize the use of air gaps in conjunction with fiber based armor materials. Ceramic tiles having gaps without grout in-between the tiles may have been used to achieve material flexibility for a rigid material like ceramic. However, the present teachings recognize the utility of air gap layers in non-rigid fiber based materials. Present teachings also recognize advantages of air gaps of different sizes based on the location of the particular air gap layer in an armor system.

Air gaps may also have been encapsulated within composite panels for ballistic protection to serve as ventilation holes for out-gassing when the composite is produced. In contrast, the present teachings, according to some embodiments, recognize use of air gaps layers in between layers of armor therefore placing fibers comprised in the layers of armor in a state of tension when they flex backwards into an air gap following impact by a projectile. Teachings of the present invention according to some embodiments recognize benefits of specific locations, directionality and/or size of air gaps in contrast to generally embedding air gaps within a material.

Air gaps have been placed behind layers of steel-based armor to protect against shaped charges. In contrast to the present teachings, these steel based armor systems in fact had more devastating impact from shape charges as the configuration of air gaps allowed the steel to stretch out into a longer ductile channel causing the shape charge to slide through layers of steel with greater ease.

Teachings of certain embodiments with regard to the present fiber-based armor panels have shown that air gap layers having one or more characteristics as described in the present specification provide protection from shape charges and EFPs.

Teachings of certain embodiments recognize the use of air gaps fine tuned to have a thickness d that is selected and/or determined based on location of the air gap within the armor system in relation to the direction and force of impact.

Modifications, additions, or omissions may be made to the systems and apparatuses described herein without departing from the scope of the invention. The components of the systems and apparatuses may be integrated or separated. Moreover, the operations of the systems and apparatuses may be performed by more, fewer, or other components. The methods may include more, fewer, or other steps. Additionally, steps may be performed in any suitable order. Additionally, operations of the systems and apparatuses may be performed using any suitable logic. As used in this document, “each” refers to each member of a set or each member of a subset of a set.

Although several embodiments have been illustrated and described in detail, it will be recognized that substitutions and alterations are possible without departing from the spirit and scope of the present invention, as defined by the appended claims.

To aid the Patent Office, and any readers of any patent issued on this application in interpreting the claims appended hereto, applicants wish to note that they do not intend any of the appended claims to invoke paragraph 6 of 35 U.S.C. §112 as it exists on the date of filing hereof unless the words “means for” or “step for” are explicitly used in the particular claim. 

1. An armor system comprising: a plurality of layers of armor; a plurality of air gap layers located in between two or more layers of the plurality of layers of armor, each air gap layer located at a respective depth in the plurality of layers of armor, wherein at least a first air gap layer of the plurality of air gap layers is located at a first depth from an outer side of the armor system, the outer side being located toward a projectile impact site; at least a second air gap layer of the plurality of air gap layers is located at a second depth from the outer side; and the first air gap layer has a thickness greater than the second air gap layer.
 2. The armor system of claim 1, wherein at least one of the air gap layers further comprise an easily yielding material.
 3. The armor system of claim 2, wherein the easily yielding material is a gas, a soft material, a material having very little structural support, or a material having strong structural support.
 4. The armor system of claim 1, wherein at least one of the plurality of layers of armor is comprised of fiber made materials.
 5. An armor system comprising: a plurality of layers of armor; a plurality of air gap layers located in between two or more layers of the plurality of layers of armor, each air gap layer located at a respective depth in the plurality of layers of armor.
 6. The armor system of claim 5, wherein at least a first air gap layer of the plurality of air gap layers is located at a first depth from an outer side of the armor system, the outer side being located toward a projectile impact site; at least a second air gap layer of the plurality of air gap layers is located at a second depth from the outer side; and the first air gap layer has a thickness greater than the second air gap layer.
 7. The armor system of claim 6, wherein the plurality of air gap layers includes a third air gap layer, the third air gap layer located at a third depth from the outer side.
 8. The armor system of claim 7, wherein the third depth is greater than the second depth and the thickness of the third air gap layer is less than the thickness of the first air gap layer.
 9. The armor system of claim 5, wherein at least one of the plurality of layers of armor is comprised of fiber made materials.
 10. The armor system of claim 9, wherein the fiber made materials comprise e-glass, s-glass, an aramid, carbon fibers, aluminum fibers, or carbon nanotubes.
 11. The armor system of claim 5, wherein at least one of the air gap layers further comprise an easily yielding material.
 12. The armor system of to claim 11, wherein the easily yielding material is a gas, a soft material, a material having very little structural support, or a material having strong structural support.
 13. The armor system of to claim 12 where the material having strong structural support has a honeycomb structure.
 14. The armor system of to claim 12 wherein the soft material is a styrofoam, a plastic or an aerogel.
 15. The armor system of claim 12 wherein the gas is air, an inert gas, oxygen or any combination thereof.
 16. The armor system of claim 5, operable to improve resistance to impact by a shape charge, an explosively formed penetrator (EFP), an improvised explosive device (IED), a ballistic device or a hypervelocity impact.
 17. An armored vehicle, comprising: a vehicle having an armor system operable to enhance resistance to a shape charge, an EFP, an IED, an ballistic device, an explosive device or a hypervelocity impact, the armor system comprising: a plurality of layers of armor; a plurality of air gap layers located in between two or more layers of the plurality of layers of armor; each air gap layer located at a respective depth in the plurality of layers of armor; and each air gap layer having a different thickness.
 18. The armored vehicle of claim 17, wherein at least one of the air gap layers further comprise an easily yielding material.
 19. The armored vehicle of claim 18, wherein the easily yielding material is a gas, a soft material, a material having very little structural support, or a material having strong structural support.
 20. The armored vehicle of claim 17, wherein at least one of the plurality of layers of armor is comprised of fiber made materials. 